| Contrast enhanced magnetic resonance angiography (1) (CE MRA) has become the clinical reference standard for arteriography. In contrast-enhanced magnetic resonance angiography, high signal-to-noise ratio (SNR) is desired to visualize small arteries. At the same time, sufficient temporal resolution is required to image the dynamics of the blood flow, which may be critical for accurate diagnosis and treatment for various vascular diseases.;Despite the successes of CE MRA in many applications, X-Ray digital subtraction angiography (DSA) remains the current clinical standard for time-resolved angiography because of its superior spatial and temporal resolution, although it is invasive, requiring catheterization, ionizing radiation, and nephrotoxic contrast agents. In long term, the objective of this research is to improve the current time-resolved CE MRA techniques to achieve high spatial and temporal resolution comparable to X-Ray angiography and potentially replace the invasive and complicated X-Ray angiography with MRA.;In the first part of the thesis, improvements made to the CE MRA, as well as the basics of magnetic resonance imaging (MRI) are covered. Topics include basic MR physics, contrast agents, radial imaging, and sliding window reconstruction. In the later chapters, original technical contribution to the field by the author is covered, which includes quantitative evaluation of Highly Constrained Projection Reconstruction (HYPR) and a newly developed technique called CAMERA (Contrast-enhanced Angiography with Multi-Echo and RAdial k-space). Finally, clinical applications of the developed techniques are discussed, which includes studies on renal perfusion and pulmonary hypertension. |
